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Rats and mice cause severe biodiversity impacts worldwide, including in New Zealand, where poisoning campaigns are undertaken on the mainland and offshore islands using cereal-based baits. However, bait stations are often irregularly serviced so wildlife managers require a bait that would remain palatable to rodents for at least 6 months in the field. One potential way to improve the field life of baits is by coating them in materials that reduce water uptake and subsequent mould growth. However, these coatings must be palatable to the rodents. This report investigates the palatability to captive Norway rats (Rattus norvegicus) and mice (Mus musculus) of both weathered and unweathered rodent food pellets coated with various polymer solutions. When compared with uncoated alternatives, fresh baits coated with shellac or polyvinyl butyral (PVB) in ethanol solvent were preferred by the rats. The use of acetone rather than ethanol solvent did not affect bait palatability. A combination of shellac and PVB reduced palatability compared with shellac alone. Weathered shellac-coated baits remained more palatable than uncoated fresh pellets to rats for up to 6 months and outperformed the PVB and combination coatings. Overall, the palatability of fresh-coated baits was lower for mice. The PVB-coated baits had lower mean palatability scores than the shellac-coated baits but none of the bait types was significantly less palatable than uncoated baits. The shellac-coated baits remained palatable to mice for up to 4 months. Shellac is recommended as a coating for multi-species rodent baits.

BACKGROUND: Invasive mammalian pests have inflicted substantial environmental and economic damage on a worldwide scale. RESULTS:Overthelast30yearstherehasbeenminimalinnovationinthedevelopmentofnewcontroltools.Thedevelopmentof new vertebrate pesticides, for example, has been largely restricted due to the costly and time-consuming processes associated with testing and registration. CONCLUSION: In this article we discuss recent progress and trends in a number of areas of research aimed to achieve long-term population suppression or eradication of mammalian pest species. The examples discussed here are emerging from research being conducted in New Zealand, where invasive mammalian pests are one of the greatest threats facing the national environment and economy. c � 2013 Society of Chemical Industry

A new low-concentration formulation of Feracol® paste containing 0.4% concentration cholecalciferol was tested for efficacy against possums in cage trials, and against possums and rodents in a single unreplicated field trial. A new low-concentration 0.4% cholecalciferol cereal pellet was also tested in the field against possums and rodents. 20 wild-caught possums, held in individual cages, were presented with 15 g of 0.4% cholecalciferol paste. Possum body weight, amount of paste eaten and days until death were recorded. The field trial occurred on Banks Peninsula, Canterbury, from September to November 2009, using a treatment site of c. 100 ha and a non-treatment site of c. 200 ha. The treatment site was divided into two even blocks, one for paste and one for pellets. Pre- and post-monitoring were carried out using leg-hold traps for possums, and tracking tunnels for rodents. Of the 20 caged possums, a kill rate of 89.5% with an average time to death of 7.0 days±0.41 SEM was achieved, similar to...

Omnivory is common among arthropods, but little is known about how availability of plant resources and prey affects interactions between species operating at the third and fourth trophic level. We used laboratory and field cage experiments to investigate how the provision of flowers affects an omnivorous lacewing, Micromus tasmaniae (Hemerobiidae) and its parasitoid Anacharis zealandica (Figitidae). The adult lacewing is a true omnivore that feeds on both floral resources and aphids, whereas the parasitoid is a life-history omnivore, feeding on lacewing larvae in the larval stage and floral nectar as an adult. We showed that the effect of floral resources (buckwheat) on lacewing oviposition depends on prey (aphid) density, having a positive effect only at low prey density and that buckwheat substantially increases the longevity of the adult parasitoid. In field cages, we tested how provision of flowering buckwheat affects the dynamics of a four trophic level system, comprising parasitoids, lacewings, pea aphids and alfalfa. We found that provision of buckwheat decreased the density of lacewings in the first phase of the experiment when the density of aphids was high. This effect was probably caused by increased rate of parasitism by the parasitoid, which benefits from the presence of buckwheat. Towards the end of the experiment when the aphid populations had declined to low levels, the effect of buckwheat on lacewing density became positive, probably because lacewings were starving in the no-buckwheat treatment. Although presence of buckwheat flowers did not affect aphid populations in the field cages, these findings highlight the need to consider multitrophic interactions when proposing provision of floral resources as a technique for sustainable pest management.

Author(s): Ross, James G.; Sam, Shona | Abstract: Possum numbers have been significantly reduced in many regions of New Zealand. However, research has indicated some unexpected consequences of possum control. At some sites, rat numbers have more than doubled 2 years after possum control. What this suggests is that the removal of a direct competitor has enabled a rapid increase in rat numbers relative to slower possum recovery. This has serious implications, as high rat numbers could inhibit ongoing possum ground control. To investigate this, an experimental trial was run where we tested the following research hypotheses by manipulating the rat density: i) Null hypothesis (H0) ‒ rat density has no influence on possum foraging behaviour around bait stations, ii) Alternative hypothesis (H1) ‒ rat density indirectly influences possum behaviour by removing all bait before possums can access it, and/or iii) Alternative hypothesis (H2) ‒ rat density directly influences possum behaviour by physically excluding them from bait stations. The experimental site was divided into 2 parts, a treatment block and a control (non-treatment) block. Rat control was undertaken using Victor® kill traps and 96 rats were removed over 6 nights (density estimated at 4.6 rats/ha). To quantify the effect of rat density on possum foraging behaviour, non-toxic bait stations were stapled to a tree every 10 m along 18 monitoring lines (n = 50). Possum behaviour was then monitored using both modified tracking cards and IR camera traps. Prior to trapping, 92% of all the baits were removed by rats on the first night. Following trapping, this reduced down to 8% in the treatment block. Rats turned up earlier than possums at the majority of the monitored sites (~1 hour before sunset). Before trapping, baits were only available 33% of the time when a possum visited a bait site (n = 15), and no baits were removed. After trapping, baits were available 100% of the time and 2 baits were removed by possums. These results support H1 and suggest that the smaller-bodied competitor can dominate food resources in NZ forests. This has the potential to make possum ground control more difficult when using control techniques that do not target rodents.

The success of research in integrated environmental and natural resource management relies on the participation and involvement of different disciplines and stakeholders. This can be difficult to achieve in practice because many initiatives fail to address the underlying social processes required for successful engagement and social learning. We used an action research approach to support a research-based group with a range of disciplinary and stakeholder expertise to critically reflect on their engagement practice and identify lessons around how to collaborate more effectively. This approach is provided here as a guide that can be used to support reflective research practice for engagement in other integration-based initiatives. This paper is set in the context of an integrated wildlife management research case study in New Zealand. We illustrate how multi-, inter- and trans-disciplinary approaches can provide a framework for considering the different conversations that need to occur in an integrated research program. We then outline rubrics that list the criteria required in inter- and trans-disciplinary collaborations, along with examples of effective engagement processes that directly support integration through such efforts. Finally, we discuss the implications of these experiences for other researchers and managers seeking to improve engagement and collaboration in integrated science, management and policy initiatives. Our experiences reaffirm the need for those involved in integrative initiatives to attend to the processes of engagement in both formal and informal settings, to provide opportunities for critical reflective practice, and to look for measures of success that acknowledge the importance of effective social process.

Author(s): Eason, Charles; Murphy, Elaine; Sam, Shona; Ross, James; Blackie, Helen; Henderson, Ray; Shapiro, Lee; MacMorran, Duncan; Gibson, Troy; Gregory, Neville; Conole, Daniel; Rennison, David; Brimble, Margaret | Abstract: Anticoagulant compounds are likely to play an important role in the control of commensal rodents for crop protection and conservation for the foreseeable future. However, there are concerns regarding their persistence and the development of more widespread resistance. We are seeking to retrieve and retain older alternatives as well as developing novel rodenticides. Our three-pronged approach is, firstly, to improve the performance of older non-anticoagulant rodenticides, such as sodium fluoroacetate (1080) and zinc phosphide; secondly to optimise the performance of 1st-generation anticoagulants; and thirdly, to identify alternatives to anticoagulant rodenticides with the same mode of action as para-aminopropiophenone (PAPP), which was registered in New Zealand as a predacide in April 2011. Zinc phosphide was also registered in New Zealand for the first time in 2011, and combinations of ultra-low-dose cholecalciferol with first generation anticoagulants are being advanced to provide the performance characteristics of a 2nd-generation anticoagulant with a lower risk of bioaccumulation and secondary poisoning.

Author(s): Eason, Charles; Murphy, Elaine; Ogilvie, Shaun; Blackie, Helen; Ross, James; Kavermann, Mathew; Sam, Shona; Statham, Mick; Statham, Helen; Lapidge, Steven; Humphrys, Simon; Henderson, Ray; MacMorran, Duncan; Gibson, Troy; Gregory, Neville; Harrison, Joanne; Giles, Gregory; Sammut, Ivan; Jansen, Paul; Conole, Daniel; Rennison, David; Brimble, Margaret | Abstract: In New Zealand, sodium fluoroacetate (1080) has been used for vertebrate pest control for several decades. Since the 1990s, some 1080 users have switched to brodifacoum for possum and rodent control because of its ready availability and ease of use. An awareness that field use of brodifacoum results in persistent residues provides the impetus to develop alternatives and provide new tools and greater flexibility. Looking to the future, we seek toxins which increasingly combine “low-residue” characteristics with humaneness, and more selective bait and delivery systems enabling better and more acceptable control of possums, wallabies, mustelids, rodents, feral cats, and rabbits. Experience gained in the 1990s with the introduction of cholecalciferol (Feracol®) and a cyanide pellet (Feratox®), which both kill possums without secondary poisoning, underpins the extension in 2009 of the Feratox® registration to include introduced Dama wallabies. To date, zinc phosphide has not been registered in NZ, despite its field use in Australia and the U.S. and low secondary poisoning risk compared with 1080. Research and registration dossiers are being assessed in 2009-10 for zinc phosphide containing products for possum and rodent control. Registration documents are also being prepared for a combination of cholecalciferol and coumatetralyl to provide a slow-acting alternative to brodifacoum for the field control of possums, rodents, and rabbits with low risk of bio-accumulation. Anticipated timelines for product availability are 2010 (zinc phosphide) and 2011-13 (cholecalciferol and coumatetralyl). Our intention now is to move beyond these conventional rodenticides and develop new vertebrate pesticides. For example, we are pursuing the registration of para-aminopropiophenone (PAPP) for humane control of stoats and feral cats, and a series of related novel toxins and other compounds that target the red blood cell for other pest species including rodents. PAPP products should be available in 2010, subject to registration approvals. New research initiatives in 2010 will increasingly result in a shift in focus to the development of novel rodenticides aided by new international research collaborations.

Author(s): Sam, Shona; Ogilvie, Shaun; Paterson, Adrian; McIlroy, John; Eason, Charles | Abstract: The use of infrared-flash camera traps has increased dramatically over the past ten years particularly for capturerecapture population studies of distinctly-marked species. However, to use capture-recapture with the more inconspicuous species, high-quality colour imaging (and therefore white flash) is required. A potential problem with white flash is that it may negatively affect behaviour, in this case at bait stations, therefore causing results that do not truly represent possum activity. Possums were used in this study to compare two different types of camera trap: infrared and white flash. Camera traps were placed to take images of possums visiting bait stations, and the number of possum visits was used to determine if white-flash cameras gave different results to infrared-flash cameras. The white-flash cameras had slightly higher possum visits than infrared-flash cameras but the difference was not significant (P=0.437). Over time, the number of possum events (P=0.62) and the amount of time possums spent at the stations did not differ significantly (P=0.81). There was also no difference in the amount of bait taken by possums at white flash compared to infrared stations (P=0.61). Results show possums are not likely to be affected by white-flash cameras compared to infrared-flash cameras. This study therefore showed that there is unlikely to be any behavioural disadvantage in using white flash over infrared, allowing white-flash cameras to be investigated for their potential in identifying individual possums, and as a monitoring tool in control operations.